KC,
I went through the whole swap and resell idea also but I strongly suggest you wait for a damaged E55 or CLk55, they will turn up I'm sure!
The only problem I have found with the entire clk55 swap is the rear windows not being recognised by the EIS, I think the only way around this will be to make the CLK55's ECU virgin again ,use the C43's EIS and recode the clk55 ECU with C43 VIN and let them get married... we will see
Good luck with the suspension, I find that part of tuning really hit and miss!(usually more miss's )