Disting does all you need.
-- John_V
Except for having the ability to move a micro SD card from it to a PC for loading.
And to the OP: that's a function that any sampler you get should have these days. You can do much more in the assembly and processing of signals for looping in the computer, then moving those results via the card to the sampler. Also, another very effective way of dealing with sample length limitations is to set up a bunch of related or even near-identical on the card for simultaneous playback. If these sample loops are of inequal length, you'll get a backdrop that's constantly in flux and, if you do the math right, COMPLETELY non-repeating. This is how I can use a fairly limited device like the Zoom ST-224 as a "background generator"; if I have several similar stereo loops running at the same level but with no means of synchronization, this sounds indistiguishable from a single stereo background track.
An example: let's say you've got four loops: 0:30, 0:27, 0:11, and 0:18. Start them at the same time, and then the next time those will line up in that way will be nearly 45 hours later (30 x 27 x 11 x 18 / 60 / 60 = one period of all loops). Pretty effective, really.