I also had a real Adlib card, but as I never had any use for it back then I sold it quite cheaply to a classmate, and now I wish I didn't.
I understand the feeling of having an original card, but I am also tempted to get a cloned card because it uses the same parts, so essentially it would sound the same as original card when it was new. As I already have two different OPL2 cards already, I am too lazy to get an Adlib clone to just get the identical analog audio path. I bet the OPL2 SoundBlaster cards I have do not have as good DAC reconstruction filter, if any at all, so I can't be sure if it would sound better or different, but I acquired the OPL2 cards for digital capturing anyway.
I am also tempted to make or hack an "improved" clone, with better or switchable op-amps, better separation of analog and digital portions of the card to battle noise, and perhaps additional high quality line output without the speaker amplifier in the path. It would also be simple to add an audio ADC and SPDIF transmitter for digital output with standard sampling rates, as direct digital output would require some CPLD/FPGA stuff to receive "floating point" audio and convert the sampling rate. Anyway, it might not be an "improvement" to other people.
As many older PCs today still don't have an ISA slot to put the card into, by poking around with game music drivers (or by making some IO port-trapping protected mode thingy), it could be possible to put the Adlib clone into IDE slot. Or just recreate the Adlib as PCI card that would sit in the standard Adlib address. I know people have put Adlibs to parallel printer ports and hacked some music players to support it.