My ideal setup:
Amiga 1200 desktop
BlizzadPPC and blizzardvision (if you can get them)
Wireless pcmcia card
Subway USB contoler for clockport
Indivision AGA internal flickerfixer
I'd get an A4000D instead.
CyberStormPPC (all CSPPC has SCSI on them, as opposed to BPPC, and the SCSI is much faster than on a BPPC)
CyberVision64 (because of the build in monitorswitcher)
Ariadne I ethernet card (admitted, it's not wireless, but ethernet bridges has been invented)
Deneb USB card, with build in flashrom
Arxon scandoubler
Maybe even throw in a Toccata sound card, and connect a MAS player.
The above makes you ready for OS3.x, OS4, MOS and with a single screen setup.
I'd say the A4000 and A1200 is on par in terms of expandebility. Often it's easier to get parts for an A1200 though, and often cheaper too.