The last true Abarth was an integrale, more specifically the rally cars which were run by Abarth.
After demise of the rally team, Abarth was broken up and many of the engineers went to work for Astra Racing who bought up all the Abarth stock from Fiat which you can still buy to this day for your 'grale, including the gearbox's, carbon driveshafts etc if you have lots of cash, like £12K+ for Abarth gearboxes.
The old Abarth factory is now gone, as all Abarths(rally/race cars) were built independently from the normal stuff.
You have to remember Abarth the brand were not exclusive to Fiat although owned by Fiat since '69 IIRC, they used to make Simca's which were French and owned by Renault, and did aftermarket tuning goods to help fund the rallying activities including cams and exhausts for E30 BMW's amongst others, old/new stock on occasions still crops up on ebay.
Though I believe Abarth in most peoples eyes is associated with Fiat and as such should be kept like that so as not to confuse the general public. Though with some form of education, maybe through slick advertising campaigns showing integrale's ripping through the Keilder Forrest back when rallying was good and seeing the Abarth overalls that were worn by the pit crew perceptions could change.
But I believe HF should be used for high performance Lancia's, not Abarth, though with the new model for the Fiat group of cars I can't really see any coming soon unless new Fulvia is actually realised.
HF it could be argued have much much more heritage than Abarth did, it goes all the way back to Fulvia's, Stratos', 037 Rally, Delta S4 7 integrales all of which excepting the S4 were world championship winning cars, though of course built and run by Abarth.
Abarth as a brand has to be kept to smaller cars to start with until brand is built up as this is where its heritage is.
Cloverleaf, hasn't quite got the cache of either Abarth or HF, but this could be changed by relaunching an Alfa in the World Touring Cars series and using it to promote the image, well if they win that is, but going on previous performances should be competitive.
And no you can't get a RHD EVO unless it has been converted by either Mike Spence or John Whally from new using RHD dash board and some nasty Fiat Regata steering rack which is meant to by poor when compared to LHD cars which have beautiful steering feedback and feel.
There is a nice integrale FE (final Edition) for sale at present in Belgium in a Citroen dealership???????? that has less than 3000KLMS on it from new, yours for a bargain 70,000Euros!
Of course there are cheaper examples out there