PADI's Tec 40 certification does allow you to do up to 10 minutes of decompression at a maximum depth of 130 feet using up to 50% O2 for decompression.@Bent Benny I think you want to have a look at PADI Tec 40.
I am not a PADI diver. @boulderjohn could definitely answer this.
As for doing it in a single tank, it is possible to do so if you use a single tank with a dual valve. You have to have two regulators on your primary gas supply so that if one fails, you can shut it down and go to the other. That is pretty rare, though. A more common approach (I assume--haven't seen it) would be to use a single tank with a pony bottle, which is also acceptable because of the two regulators. Every student I have ever had is taking the course as preparation for full tech diving, so they are using full doubles, either backmount or sidemount.
With the growing trend to using using pony bottles on routine recreational dives, I would think the idea of getting more bottom time through a program like this would be popular. With a pony bottle, you are supposed to finish the planned dive on your primary gas with the pony in reserve. That would satisfy the requirement for the Tec 40 course as well. For your post course diving, you don't have to have a separate deco gas on your dive if you don't want to. The only difference between a basic recreational dive with a pony and a Tec 40 dive with a pony could be the fact that with the latter you can violate NDLs and do up to 10 minutes of deco.