you're correct--the sony would only output redbook, not SACD to the dac. i believe there are a few players that will output DSD over HDMI as well as a number that will output DSD over iLink, firewire or other uncommon interfaces, but you're talking much bigger bucks. essentially, if you kept the sony, you'd connect digitally to a dac and use the analog outs of the sony directly to your amp for sacd.
all that said, then, the denon 2910/3910 are genuinely great sounding players with very good inboard dacs--not the most reliable, but i see 'em used for as low as $150 or so, so that might be a way to go. i personally own a pio elite 59, which is very competent, and also a good inexpensive choice, though i prefered the denon for music