Well, as a bit of history, Mini was the format that replaced SD in mobile products. Shortly afterwards, as devices got increasingly smaller, and internal space became more precious, microsd was created. Since MiniSD no longer had any use, the format was killed at I believe the 2gb size and no further updates were ever made, nor are they planned that I'm aware of, since almost nothing uses the format anymore. Thus you're best to just use a mini->micro adapter.

Oh, and btw. Those will be around for a while. However, I'd suggest stocking up on a few extras, as the adapters may soon become hard to find too since the format is dead. I may be wrong and the adapters may be around a very long time. However, recent history has shown that companies are very fond of obsolescing formats and throwing them aside for new ones once they're officially declared "dead".

That's mostly for two reasons. The first is the need to discontinue production and eliminate stock of "dead" formats/devices/etc, and the second is to force users to upgrade to newer, more profitable devices and products.