There are a few people in the LAA actively pursuing that.
It is common practise here in the US, where you just need an IR and the specified equipment (DME, ADF not needed unless you're shooting an approach that calls for them).
Flying IFR in Class G airspace is virtually undetectable and quite within the capability of suitably trained pilots in suitably equipped aircraft whether homebuilt or otherwise.
Maybe worth checking on the LAA boards what the current status is.
The RV8's a great plane anyway, but most people would want some kind of autopilot for regular IFR flying.