Paul Thurrott's Supersite has a Slipstreaming Windows XP with Service Pack 2 page. It even shows you how to create a bootable CD with it.

Maximum PC has a page that shows you how to include RAID drivers, so the SATA drivers should be the same. It's a bit complicated, though, and I'm sure there's an easier way, so Google is your friend.

This won't invalidate your product code, provided you use the same edition of Windows to create the CD (i.e. Retail vs OEM vs volume-licensed).

Oh, and the USB floppy drive support is done by the BIOS, at least during initial setup, so see if there's a setting you need to tweak.

Personally, I'd do the slipstream thing, mainly because you'll need to support bigger disks and arcane bits of chipset (particularly USB bits and bobs), and I'm not sure that SP1 includes that support. Also, you'll want to install SP2 after you've installed anyway. This way's quicker.