I think US should just offer an MHS angled piece to plug into whatever hilt you want. I think if you just had an angled piece to put on, say, and Initiate V3, you could come pretty close to the look and size of Dooku's hilt. The insides would not need to be altered, it would just be like a longer pommel.
This might be an ideal solution for the kind of hilt I want. I actually just ordered a Shock with just that kind of modification in mind. If US came out with that kind of a piece, I'd buy it in a heartbeat.