I have some mini sized Dean's on my Xray M18T, they seem to be the perfect size for 1/18 and should be good for your build too. I think the full sized Dean's are bit too big, and the micro Dean's are too small, but the mini's are just the right size.
They are the black ones:
http://www.progressiverc.com/index.p...emart&Itemid=1
Let me know if you get a Proton motor. I have been thinking of getting a Neutron motor (next size bigger from the Proton) for my Xray and was wondering how these little Neu's perform. I have no doubt they will be solid, like any Neu, but more wondering the 4-pole vs. 2-pole in smaller scale.