The LX90 mount is not the same as the LX200's... the LX200 has a more precise motorised mount - suppose to have larger arc seconds which is much better for photography. Hence the massive difference in price between the LX90 and LX200. (it wasn't just the apeture that was the difference.)
(the guy at the shop said something about the CPU being in the mount and not in the console or something like that amidst a myriad of other differences.....)
Meade is releasing their 10' and 12' with the LX90 mount in the next few months..... for the budget concious... still it will set us back about 4 - 6 grand.