Any electronic geniuses here?

The only thing I can possibly add to the above comments is that good transformer companies like Sowter in the UK will make a range of transformers suited to specific cartridge impedances. These are "loose" transformers that should be wired internally into the preamp which turns out to be the best way to add a transformer. No added contacts or interconnects and the transformer has additional shielding within the preamp. You just have to keep it away from AC devices like the power transformer. A good technician can make the addition 100% reversible.  

Call Big Ears Stereo out of Tempe Arizona he has a degree in electrical engineering and is very easy to talk to hope this helps you all the best

Thanks everyone for all the great info and advice.  I am looking for a 10:1 SUT so it looks like load shouldn't be unmanageable from what I've read here.  Anyone familiar with the Bryston TF-2?

Yes, assuming an ideal transformer, the measured impedance is related to the impedance at the output by the ratio of winding on the input vs. the output. 

http://www.vias.org/matsch_capmag/matsch_caps_magnetics_chap6_04_04.html

Again... not a genius but I've designed a few phono amps. Lundahl make nice MC transformers, they also have quite a bit of technical info on their website. There is also this handy tech note that provides guidance on setting up the input impedance when used with an MM stage.
If I remember correctly the data sheets for the trafos are missing some information to do the calculation for yourself but I can probably dig out a spreadsheet I've used for the calculations in the past if you can't find what you're looking for in the tech note.