Not one that got me excited by the place or period per se, but certainly an excellent narrative of Welsh history (up to the Edwardian Conquest) is available for free online:

Sir J.E. Lloyd, The History of Wales: From the Earliest Times to the Edwardian Conquest, 2 vol., 1911.

Lloyd's remains one of the seminal works of Welsh historiography. It is outdated in places and deficient in others (particularly the reign of Llywelyn ap Gruffudd (d.1282) but is written in evocative, if antiquated, prose.

Volume 1:

1. The Prehistoric Epochs
2. The Historic Dawn
3. Wales under Roman Rule
4. The Fifth Century
5. The Age of the Saints
6. Struggle of the Cymry and the English
7. The Age of Isolation
8. The Tribal Divisions of Wales
9. Early Welsh Institutions
10. The Age of the Sea-Rovers

Volume 2:

11. The Norman Conquest - First Stage
12. The Norman Conquest - Second Stage
13. National Revival
14. Owain Gwynedd
15. Rhys ap Gruffudd
16. The Close of the Twelfth Century
17. Llywelyn the Great - Early Manhood
18. Llywelyn the Great - Maturity
19. Between Two Tides
20. Llywelyn ap Gruffudd