Glad this thread popped up again. I skipped it the first time 'round as I was on vacation and knew I didn't have the time to get properly sucked in.
My background in electronic music predates MIDI and certainly any drum machine I could have gotten my mitts on. I was using analog modular equipment to generate timing - as well as an Apple ][ with an analog interface. My musical education was also rather unconventional... and so my early music had interesting metrical structures:
I was quite fond of building up metrical patterns, more like poetry feet: [: (( 3+3+3+2+2 ) x 3 + 3+3+3 ) x 4 + 2+2+2+2+2+2+2+2 :] -- I could make my synths play this. I had a sense of how one might use time signatures to notate it... but it didn't seem to help matters much!
I wrote pieces based on change ringing (see, for example a later work Plain Changes 2). Here, changes of n bells use phrases of n+n+1 beats. These compositions overlaid changes of 3, 4, 5, 6 and 7 bells - or overlaid 7, 9, 11, 13, and 15 beat structures. Polyrhythmic perhaps - but certainly not in the "conventional" sense.
I also wrote many other pieces based on various algorithms - these had a pulse, but no clear sense of metrical structure at all: For example, a work based on neuron networks had a regular neuron firing rate (the pulse) - but how many pulses per phrase was essentially stochastic.
I bring this all up to point that I've found it electronic music lends itself to naturally explore not just uncommon time signatures, but the whole nature of metrical expression. It is practical to build electronic systems that let one explore and perform complex structures.
Since then I've spent a few years studying conga drumming - and more recently making my share of 4/4 techno-ish beats. I feel like I've grown to feel rhythm in my body and not just in my software. And I've returned to those early built up patterns, only this time learning to playing them more by feel than by composition. (For example Count With Me (disquiet 0269).)