How about dropping support for LESS and using SASS instead?
Looks like there is already a SASS port:
I personally think SASS has won out over LESS since the introduction of SCSS and if Bootstrap dropped support LESS would gradually fade away.
Since the differences are so marginal I wish projects would pick their preprocessor by the number of available implementations (in popular languages) rather than the latest fashion.
Less and stylus only have javascript impls and should be avoided for that reason alone. The same applies for most other niche processors.
Like it or not, SASS appears to be the only one with a C library that enables a wide range of language bindings.
I came across this: https://github.com/duncansmart/less.js-windows
It leverages the fact that windows has long supported running JavaScript (OK technically "JScript") outside of the browser, without node, to create a command line utility from the less.js implementation. Works perfectly :)
Even if you don't officially sanction or provide a port yourself -- just hearing that you're open to tweaking the way you do things a bit to make it easier for _others_ to port to Sass (and keep their ports up to date with bootstrap evolution) -- is super encouraging.
I'd actually suggest that as a first step, just talk to the folks maintaining the ports, and ask if there's anything you can tweak on your end to make their jobs easier.
You shouldn't be running less.js in production.