A typical service online (and perhaps in your area- search google maps) will charge 35 cents per slide. At least that's what
www.thedigitalconvert.com has listed after my quick search in Chicago. So 1,000 slides would be $350. You spend zero time doing work and you'll probably get a better job done. Flatbed scanners make sense for casual use. For large jobs, it's not worth the time or effort.
The Epson V700 costs about $500 and does a super job. But I can tell you from much experience that it is not very fast. And if you're planning on turning on the native dust removal you really can forget about it. As for the third-party built-in Digital ICE - it's so slow it's practically useless. Not to mention it overcompensates and terribly messes up your scans. I vote 2 thumbs down for flatbed Digital ICE. Seriously. The native dust removal is fine but slows things down some.
With all features off, it will take almost of week of scanning FULL-TIME to get through those thousand slides with a flatbed. Not to mention the time you'll need to learn and get comfortable enough with the equipment to move fast. And the V700 is probably your best bet in flatbed as it can do 12 at a time. The high-model Canon can do 12 as well although my trust has always been with Epson.
The Nikon scanners most people use for this are out of the typical person's budget at about $1,500 with the 50 slide feeder attachment. Those aren't trouble-free either. And with regard to dust removal, personally i'd rather apply it myself in software than let the scanner overdo it on all my pictures and ruin ALL my scans.