There are hard top SW20 turbo's for sale on carsales currently for around 7k.

Can't you just weld some roof panels in place of the targa tops if that desperate for a hard top?

I'm not really sure what you are talking about with importing and doing all the other stuff (too much technical stuff does my head in, lol).  But there is this one on carsales.  I took it for a drive a couple of weeks ago.  Drives nice.  Very trustworthy club member. It's an easy 3ish hour drive down the highway from Newy.
http://www.carsales.com.au/private/details/Toyota-MR2-1994/SSE-AD-2899492/?Cr=6&sdmvc=1

Thanx for your input guys :-) - I was just wondering if its been done before? I know it has with other vehicles with sun roofs. I'll just try cold calling around some resto shops and ask directly if it can be done.......and the cost - clearly "anything" can be done but I do have a budget limit (unfortunately)  :-) 

it just seems like a really round about way of getting a hard top (buying 2 cars for one).
 
But like you said, anything can be done, for a price.

Unfortunately, due to the import regulations in Australia, importing any Gen3 HT and getting it registered on the road is pretty much impossible, unless (correct me if I'm mistaken) it's a personal import that you have owned overseas for 2+ yrs.
 
A Gen3 HT is indeed a nice idea, and it's a shame Toyota didn't release more over here in the later years.
So in reality - your options are;
Live with an ADM Targa (like a nice Bathurst edition!),  or get yourself a slightly older Gen1-2 HT here and apply TLC to make it as mint as you can afford.

I've got a gen 3 hardtop (genuine SW20 GTS Gen3) and it was street registered and not a personal import. Can still be street registered again but has a few mods on it.

Hmmm sounds interesting - Assume you only track the car now but sounds like it meets compliance? Are you at liberty to disclose more about how you got your car & its history?

I also have a Gen 3 GTS hard top, it was damaged in Japan with just 10 K on the clock. It is not to be registered in Australia. The importer sold it to me for parts. One day when it is thrty years old it may be alowed "club rego" in NSW.
This GTS was imported with the strict condition that it not be registered.

mr2twanted
Hmmm sounds interesting - Assume you only track the car now but sounds like it meets compliance? Are you at liberty to disclose more about how you got your car & its history?

I just bought it from a  guy here in Melbourne. It was fully compliance and registered. He had an engineers on it as well because of the modifications but isn't a repairable write off or anything. It's just a imported GTS Hardtop which has been modified. I didn't want to pay rego every year because I'm only using it as a track car so didn't bother registering it. He used it as his daily however and was fully registered. It's very low to the ground with a  big carbon front splitter so not able to drive everywhere on the streets also why I didn't register it. Has the compliance plates and all bolted to the firewall.