If you were around when Custom Housing came out then you would know for a fact that with the current UO programing that it is
"technically impossible" to do what you ask. I think it was Wilki that explained it to us.
There are 3 housing types that can not be customized
- L-Shaped require 2 housing plots to build
- Keep and Castle require 4 housing plots
- Large Tower when you customise it loses its wings.
The program itself only understands an 18x18 plot as the largest plot it can place and the programers had to go into the program itself and join the above mentioned houses together. If you could customize a L-Shaped, Keep or a Castle with the current programing and housing rules then you would end up with 1 18x18 plot and lose all other plots required for these designs or you would have to submit your design to a dev and they would have to build it for you and link all the plots back together. So yes it is
"technically impossible" to do what you ask.
Now it you are asking the current Devs to rewrite the current Housing part of UO to allow this then please
NO. There are a lot of plots out there that would be lost or the Devs would have to go and remove a lot of the house blocking items to allow a 31x31 plot.
Please Devs do not mess with the current housing part of the UO program as we have no clue what other problems this may cause. And just for info do those other non-namable shards have 31x31 plots?