I knew DOS had to have sold well, because it took me about 2 months to buy a copy.
It was literally sold out on every shelf in my city, there wasn't even external stock available. I ended up importing it from the UK. (and yes, She was all that)
The 3DS is a great console, and would be prime for more DS castlevania, the only thing I fear is that for commercial games (MOF, ALBW, etc) the majority all seem to use 3D graphics which has worked well for some franchises and not so much for others. What I'm saying is potentially for a new 3DSVania, if it isn't a 2D game with sprites and pixels then it really doesn't interest me. 3D CV will always belong to consoles, true 2D CV should retain its position on handhelds.