That'll be an all-in-one then ... have a look at PC-Chips M810LR (SiS 730S chipset, SDRAM) or M841LR (SiS 740, DDR or SDRAM). These include graphics, 4-channel sound, modem and 10/100 LAN right out of the box. 841LR is the newer and much faster product (esp. when used with DDR RAM), but for that application, who cares?
If you don't have the CPU already, you might even want to consider using a 787CLR - this one brings the CPU right on the board too (a 667 MHz VIA C3, not upgradable).
I've been configuring systems with 810LR and 787CLR for exactly that purpose for friends of mine. 787CLR is good enough, 810LR however feels noticeably faster and has more headroom.
regards, Peter