The more important question here is why are you not doing this is what ever software you are using?
But in response to the question at hand...
As for tape decks the older Tascam 8 track and 2 track machines (at least the ones I have) do have a speed control but it is in the form of a pitch + or - selector with no units. There is no direct indication of how much it speeds the deck up on playback. In terms of slower speed you can always put your finger on the reel to create drag and slow the deck down as much as you like. As for speeding it up that would be tough if you want to go higher than the speed the pitch knob offers. Off the top of my head I cant think of how to do this with out hacking into the electronics. You could try to hit the fast forward button and apply some drag to the reel to get the speed you want but be warned, I have no idea what this will do to the deck. The motors in these decks are fragile and may not stand up to this kind of playing around. For what its worth tape deck companies spent a lot of time, effort, and money making sure that the deck always spun at the same speed (to ensure repeatable playback).
On a side note, tape for these decks is getting super expensive as companies are stoping production of it. You can find a used 2 track or 8 track reel to reel easily for a few hundred bucks on ebay but they are VERY heavy and I imagine difficult to ship. You may be able to get old tapes for them cheap as well but the tape wears out over time and has a very real very present recording lifetime. The old tapes also have a nasty habit of disintegrating onto the record/playback heads and gumming them up.
Another option is early tape based digital delay units. Before digital delay was invented delay units used a small loop of tape that would have a record head separated from a playback head by a small distance. A loop of tape was then placed over them and the signal put on the tape and then played back a bit further down the line. I dont remember if you moved the head or changed the speed of the tape to change the delay time. You maybe able to modify one of these units to play back a sample at higher or lower speeds if you hack into the circuitry a bit. Keep in mind these units are sought after an may show a premium in their price.