How much does the accuracy suffer compared to full barrel length models ?

No difference.

I agree.  My Chinese para shoots just as well as my Romo, Yugo and Alby.  Not that any of them will shoot one inch groups but, they are still fun, reliable rifles.

Barrel leangth means nothing on accuracy. A longer barrel will give you more velocity hence less drop at longer ranges but your grouping size should not change at all. My 20" heavy barrel .308 shoots as accurate as my Dads and my Brothers 24" rifles. You just have to know your rifle and know what the drop will be at the distance you are shooting which is with any rifle realy even if they have a long barrel. I hade a Norinco paratrooper and hocked it about 7 years ago for $75 I know they go for a lot more now.

What are the paras going for now?

AK mag type anywhere from $300-$450. Regular SKS paratrooper $250-$300. Roughly figuring, prices also vary from state to state or area to area...Nevada is notoriously high. I just paid $300 OTD private sale at a gun show for my SKS Sporter that takes AK mags. Got my regular Paratrooper for about $160 OTD private sale( been so long I cant remember).

Should be just as good.  I have had a couple and they were as accurate as my full length and in one case the short SKS was the most accurate (that was at 100yds).