looking to build a machine

[OutcastZeroOne]

Hey all, not sure if this is the right section but nothing else seemed to fit for this question. So right now I have a Lulzbot Mini but am finding that its 6"x6"x6" build area keeps getting in my way. I know that it is possible to make a larger frame for the Mini and change the settings in the program but I kinda want to leave this one alone and just build a larger machine. Ive got a source for NEMA 17 motors along with the lead screws and slide shaft and hardware. But im a total n00b when it comes to finding what controller to use. Ive searched and searched read multiple "best boards etc..." lists but an still unclear of what I would really need.

so far, to help here is a general idea of what I would like to build, keep in mind this is not set in stone.
300x300x300 build area (possibly larger)
24v operation
heated print bed
CoreXY gantry
Control LCD

Im not looking for the cheapest parts. I dont mind spending a little more to get something better. I mainly do ABS and Nylon materials. I do plan to build a full enclosure for this machine to help the materials laminate better. Any help is greatly appreciated.