Yes and no; off the top of my head, I'm not aware of any scheme to sell slaves on to Brazil in the fashion you suggest. Logistically this would have been very difficult, given the ongoing war and the increasing severity with which anti-slave trade legislation was being upheld at the time. There were, however, very similar schemes mooted - with varying success - around the end of the Civil War.

TL;DR: Several thousand confederates moved to Brazil, though many probably returned to the US. Those that did go were very, very unlikely to take their slaves with them - the migration was overwhelmingly after the war had already ended. Those that did remain in Brazil seemed likely to have relied on native labour as well as slave labour; they do not seem to have been motivated by resistance to abolition as much as out of a fear that abolition risked the end of the lifestyle and culture they cherished.

Although America had abolished the slave trade at the same time as Britain, the federal government's efforts to enforce the provisions of abolition were much less earnest than those of the British for most of the period; the US had little practical interest in enforcing the prohibition of the transatlantic slave trade outside of its own waters, and there is a debate as to just how effective the American government was at preventing slaves from still arriving illegally in the US (we have evidence of at least 8,000 slaves arriving in the US from Africa after the trade was outlawed). In light of that reality, some Americans who had financial investment in the trade simply turned their attention to involvement in Brazil; by extension, many of these individuals would have themselves been slave holders or connected to the southern planter elite.

In the dying days of the Civil War, some southern slave-holders did consider the idea of migrating to Brazil so that they might continue their lifestyle. Only a very small number of individuals were likely to have gone through with such plans though; the logistical challenges and costs of moving such a vast distance, with a host of slaves in tow, would have been immense. Furthermore, it obviously entailed transplanting oneself into a culture and society vastly different to the southern United States. For the southern elite, accustomed to a very particular kind of polite high society and having a very localised conception of what it meant to be American, such a cultural transposition would have not been an easy undertaking. Very few individuals ultimately appear to have decided to relocate with their slaves - we are talking perhaps dozens at the most here.

Significantly more do seem to have moved south to Brazil without slaves in tow, though, in the hope of finding a new life after the loss of their slaves - and often their land - possibly with the hope of finding a place in the plantocracy there, and acquiring new slaves. It isn't clear to what extent these migrants, who became known as confederados (some of whose descendants still live in Brazil today - the English dialect they speak is closer to that of the 19th century south than contemporary southern American English), were successful or on what scale migration took place; it was certainly in the thousands, but probably not the tens of thousands. Many of those individuals may have returned to the US. The biggest single migratory effort was led by former State legislator William Norris, of Alabama; he and several dozens of his associates moved to Brazil. Former Confederate colonel Archibald Dobbins from Arkansas was one of the other more notable individuals who moved to Brazil and seems to have succeeded in starting a new plantation there; movement seems to have been by large by state-based associations of families, rather than individual families or any wider southern scheme. There is some debate whether this can be seen as an act of resistance to the abolition of slavery per se or as an effort to preserve a southern way of life and economy that these individuals feared could not be sustained post-slavery; certainly many of those who moved to Brazil ended up using cheap native labour rather than slaves.

In a similar vein, some of the planters who remained behind still saw Brazil as a solution to what they now perceived as their 'free black' problem. Even during slavery there had been profound concerns about the ratio of black slaves to white citizens; though abolition had dimmed the risk of violent black uprising, it now exacerbated the threat of broader social chaos by what the white establishment perceived as the inherent disorderliness and brutishness of the ex-slaves. It was suggested that the mass deportation of blacks to Brazil (where they would, of course, be at risk of enslavement again) or other parts of South America could be a solution to this problem; if the south could not have slaves they felt, then it should at least be permitted to be a wholly white, 'civilised' society free of the burden of the black population. Unsurprisingly, these ideas didn't get very far - deporting several million people is quite a feat, and neither Brazil and nor the free black population now staking a claim to its own American identity certainly would have been very accommodating.

Ultimately though, these were the schemes of a great minority of southerners. Most would not have considered such options to be truly viable, and instead focused their attention to trying their best to 'make do and mend' in the post-bellum south.

There are two great books on this topic that spring to mind. Gerald Horne's superbly researched The Deepest South: The United States, Brazil, and the African Slave Trade (New York University Press, 2007) explores the intricacies of Brazil-America plantocracy relations, and the schemes that emerged at the end of the Civil War to try and sustain slavery or relocate to South America. Cyrus and James Dewey's older work The Confederados: Old South Immigrants in Brazil (University of Alabama Press, 1995) is an edited collection of papers that explores just what became of those ex-confederates who did move to the south, including fascinating explorations of their culture and religion, though it sadly does lack any non-Confederado context to help us understand the real significance of the migrants impact on Brazillian society (which was probably ultimately negligible). Still, both are worth investigating if you want to learn more.