Rather than mess about with samples, I'd replicate how the 808 and similar machines synthesised their kicks in the first place.
Basically a sine wave overlaid with a single "needle" pulse (to give a bit of impact) followed by slight pitch modulation.
Any synth with a resonant filter. A 24dB/octave (4 pole) Moogish one should do nicely.
Set filter to a bass-drum kind of frequency then crank the resonance until it oscillates when played. This will give a sine wave that is the drum's "boom".
One or more oscillators, set to square wave with a narrow pulse width at bass drum kinds of frequency, maybe one oscillator set around the 1-3K area mixed in.
Filter envelope should be pretty much zero attack (let's the higher oscillator through to provide "beater click"), a short and steep decay to a lower sustain (this kills most of the square wave's higher frquency components and then provides the drum "body"), zero release. Amplitude envelope very fast attack, decay to zero over however long you want the drum to sound.
Modulate pitch/filter frequency during the note a little as well if you want - it should fall slightly.
Then distort/compress/layer as seems right.