Options for Renoise-esque sample slicing?

I've been working on making a sample-mangling patch lately, which takes different sections of a buffer that are selected via sequencer, puts the start and end points into a groove~ object, and then "mangles them" in various ways. Kinda generic, I know. Up till now, I've been creating the slices with an algorithm that gets equally sized start and end times based on a note division and the sample's original tempo. This approach has been fairly problematic in that it makes using nonrhythmic samples a crap shoot, and makes preventing clicks and pops while also maintaining impact in impact sounds fairly difficult.

The ideal solution for me would be to have a system similar to Renoise, where you can put markers on a waveform (similar to in the complex warping section of groove~'s help patch) to visually see what you're slicing, as well as not have slices overlap each other like they might when using the more simple "store start and end points from waveform~ in a coll object" approach. To program this myself, I'd need to start learning Javascript (or at least I assume so, considering jsui was used for the object in the groove~ help patch), which I don't have a problem doing. But before I put in the time and effort to do that, I figure it's worth asking: does anyone know any native or external objects that I may be overlooking which already have that functionality?

Thanks in advance.