Hi and welcome to the forums, tester. It seems like its possible to put a 15.4" T61p's motherboard on an 15.4" R61. The R and T series share a lot of components, including the motherboard. However, there are modifications involved. The heatsink on the R61 may not be up to the job of handling the cooling, and the early batch of Nvidia GPUs on the T61p's motherboard do have problems so make sure to get a GPU with a late build date.
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