Awesome motorcycle! I have thought about doing that with my 250 dual sport. Put a Ninja 250 motor in there.
I had no issues with the '08 KLR. I replaced the Ninja 650 with the Versys and realized that it handled most of the roads I used the KLR on. My neighbor wanted the KLR so I let him buy it. I still get to admire it without having to maintain it.
RepsolRider's bike. He did a really nice job, build and finish quality is first rate. When I finally decided to seriously look into doing this swap I did a google search for pictures of a Versys motor to get dimensions and the first thing I found was his thread on the advrider forum. That was proof enough that it could be done and the following day I purchased my donor bike and got started. I did borrow a few ideas from his bike, the forward exhaust routing and the fuel pump can. Check it out if you like. He put up a lot of pictures.
I met up with Fritz in Mason, Tx last Saturday while he was on his way back from Moab. I was on my R1100GS, we swapped bikes for about 40 miles of highway and it was great as it just ate up the miles. It was hard to understand that I was on a KLR (I love KLR's) with that motor. Great bike and thanks for letting me ride it.
Thought I post up a few recent pictures. It's a bit more finished than the previous pictures. Now has a custom skid plate, luggage, 320mm front rotor, Progressive rear spring/shock, Progressive front springs, a power commander. Ready for travel. I rode it from San Antonio to Moab, rode the white rim trail and rode back. It did great, no problems. If I could keep it at 70 or below I would get 55mpg, but it's plenty happy doing more.
I added a Rostra cruise control. Love it. Relatively easy connection to the the Versys wiring.
Riding the WRT.
I'm currently working on KLRsys II. A 2nd gen 09 KLR with another 09 Versys powertrain.