Hi there,
Just want to chip in with some observation and opinion.
I don't use Samsung but I do have a Canon MF4380dn on my desk that I connect to via USB. With this device, I see the same thing in the Options & Supplies > Supply Levels pane; ie "Information not available". However, this has always been the case for this machine under 10.6.x and 10.5.x and I suggest this would have been the same for your Samsung. The only way I can see the toner level for this model is to open the Canon utility, which is going to be like your Samsung Smart Panel that was previously appearing.
I believe the matter that Samsung should have been helping you with is getting that Smart Panel to open again. I am confident that the Samsung tech support is using this application to see the toner level, not the Supply Levels pane.
If you open Options & Supplies, select the Utility tab and click 'Open Printer Utility', does this open the same Samsung Smart Panel you saw previously, or at least open a different Samsung utility that lets you see the toner levels. If this does open a Samsung utility, maybe there is a setting here that will enable the Smart Panel pop-up when you print.
FYI - the Apple Supply Levels pane only works with devices that report the ink or toner information using supported frameworks (core library files). My Canon inkjet shows the ink levels, as does my networked Canon colour copier using a PPD. This panel did not work on Leopard, it has only been since installing SL that I can see any ink or toner information.
Pahu