Here are some registrars I know of that take Bitcoin, they don't have the specials you are looking for though
Epik
AlpNames
DirectNIC
InternetBS
Gandi
NameCheap
PorkBun
The dollar specials seem to be more common at smaller resellers and of course Fasthosts or domfam - Domain/MyDomain/NetFirms/Dotster
When the SuperSales were running often, many of the power buyers were doing two years to save trouble, and they all said it helped them buy fewer names that were better quality.
Hopefully someone else knows a better deal for you : smile :