Their isn’t one you can get to day new because this stuff has stopped being made now so you will need to look for 2nd hand stuff.
And if your looking to go 64-bit Win 7 you very likely will not be able too with this stuff.
It's time to build or buy a new system. But for what it's worth I have an older system running Windows7 Pro, 32bit, with no problems.
Intel D845EBG2 motherboard,
Intel Pentium 4 2.53 GHz processor,
Look for a P4 motherboard with more RAM.
Although Intel does not support Win7 on the GLLY, it will work.
You'd need access to other hardware to make if fly though. If you sysprep (utility within the O/S) a drive on an existing Win 7 machine, then install the drive in the GLLY, 7 will load just fine. All the drivers it needs are in the O/S.
I've done it. It's fast and easy....and works perfectly. The only challenge is the sysprep routine itself. Best to consult with someone who knows about it. There are some parts to it that can go south on you if you don't know what you're doing.