they would never prescribe barbiturates with benzos; they're definitely counterindicated (extremely dangerous interaction there!). i'm not sure why you'd prefer benzos to barbiturates; it's my understanding that barbs were more fun, but they've been largely superseded by benzos since they're less dangerous and "less abusable".
lithium has no recreational value and I think it should be avoided anyway; it's not 1946. there are no antidepressants that have recreational value, really.
honestly, you've probably done about as well as you're going to, particularly with that klonopin. you could almost definitely get that switched for another benzo, if you look into it. klonopin has a bit of an issue with anterograde amnesia (forgetting things that happen after you take a dose, like a blackout on alcohol).
if by 'psychostimulants' you mean the sympathomimetics such as Ritalin and the amphetamines, then yes, those definitely have recreational value, which is precisely why they're hard to get. you won't get them for bipolar disorder, since they'll make the situation worse (by inducing mania, as quale said) and not better in any real way.