You could try vyvanse (lisdexamphetamine), maybe. It is essentially dexedrine that has been chemically modified so it can no longer produce an instant rush - lisdexamphetamine is inactive at first, and only becomes active after being converted to dextroamphetamine by enzymes in your bloodstream, so it tends to take atleast an hour or so for the effects to become noticeable. This is not just an "extended release" version - you cannot just crush up a bunch of beads in the capsule to turn it back into a snortable "instant-release" form.
As I said, the modification is on the molecule itself, so you could snort it all you want, but you'd still have to wait for the enzymes to do their thing.
Because it is a pro-drug for dextroamphetamine, dosage conversion from dexedrine is relatively simple - the largest available dosage of vyvanse, 70 mg, corresponds to roughly 30 mg of dexedrine.
Again, if your problem was abusing your dex by snorting it for a rush, then vyvanse might be an option for you. People with anhedonic depression unfortunately tend to easily slip into drug-seeking behavior, so while carefully adjusted doses of dextroamphetamine may prove beneficial in cases of severe anhedonia, the risk of abuse generally outweighs the benefits. In these cases, vyvanse may be a superior option, as it offers pretty much the same therapeutic efficacy as dexedrine but with a significantly lower abuse potential. In ritalin, the lower abuse potential mostly becomes from the stimulation just feeling too jittery at higher doses.
Not saying that vyvanse doesn't have a potential for abuse and addiction though; it's obviously going to get people high if they take double or triple the dosage, and patiently wait for the (much more gradual) come-up.
That said, one major problem for you is that by abusing dexedrine, you've essentially conditioned yourself to associate "therapeutic efficacy" with "a stim rush". You've got to accept that "no rush" is not the same as "this drug doesn't work"; your goal is a stable increase in focus and a decrease in anhedonia throughout the day, not an unstable cycle of euphoric come-ups and soul-crushing come-downs.
All in all, you should probably give biphentin a shot for a for atleast a month. In the initial phase after a period of dexedrine abuse, nothing is going to completely quench that stim craving (except recreational doses of your stim of choice); at the right dose, methylphenidate is an effective medication, with ER methylphenidate products like biphentin, concerta or ritalin LA still being the standard first-line treatment for ADHD outside the US.
So yeah... take care, things *will* get better once you're on a stable, sustainable dosage of the right meds... I'm speaking from experience here.