Here's the plan. It's real difficult, so pay attention.
First, you buy the DBoys AKS-74 (sold by them as the RK-03). It has a stock that folds to the side. The RK-03S version has real wood furniture and steel construction.
Then, if the barrel ain't long enough already for your tastes, put a PBS-1 or a PBS-4 suppressor on it. The PBS-1 looks cooler but is slightly incorrect (it is for the AKM, not the AK-74) while the PBS-4 is more accurate to the real steel but kind of has an odd look to it.
And there you go. Side-folding AK that doesn't look retarded with a long barrel.
Also, a note: AKs are not very long as far as guns go. Don't be surprised if you think they're shorter than they should be. (An AK-74M, the longest standard version, is still almost 7cm shorter than an M16)