Conversions of the dyna never really took off, there were a few attempts and there are some custom fans around but the cost is high for what you get, and there seems to be a need for much reinforcement to stop the blades shearing at higher RPM.
In comparison the Ramtec has moved forward with bulletproof performance and extra blades (I asked for them ) and really its one of the best turn key 5 inch fans you can get. Tony really got into converting the ramtec over to electric, he listens and knocks up test units and ideas quickly and efficiently, the Ramtec has shed weight and the revised housing is really a superb piece of work for the $$. Our current version runs the big HET 800 series inrunner and will run 12-14 cells, pushing 8+kg to over 10kg in thrust at a very manageable amp draw.
You can see all the specs and my test results including videos of the fan on the thrust stand HERE
Cost of a ready to install dynamically balanced fan works out to approx. USD$370.00 and shipping is around 47 bucks.

When you look at the cost of parts to piece together a dynamax, you can get the complete ramtec for not much more than just the fan.