Unfortunately perl can not currently be compiled using the compiler (VC 8.0)

Now that you mention it, I vaguely recall reading about that. However, ActiveState do provide a 64-bit build - so the main thing is that I at least get hold of a compiler that I can use with ActiveState's 64-bit build (even if I can't actually build a 64-bit perl myself). I have the Enterprise Architect edition of Visual Studio .NET (7.0), but I'm not sure if it has what I need in the way of 64-bit support.
I probably should have waited until I take possession of the new box before asking questions, but I was keen to put out a few "feelers" - and I'm glad I chose to do just that, as the responses in this thread have been very helpful. (Actually, SFLEX's reply wasn't all that helpful, but it sure was entertaining :-)

I found that 5.8.8 fails building at miniperl.exe

Yes, this was also reported by almut elsewhere in this thread ... it doesn't look very promising ... looks like my best bet of actually building a 64-bit perl is that my Visual Studio .NET can, in fact, deliver what I need.

Cheers,
Rob