Absolutely. The iPod Mini is a usable device that can be modded. The only thing I'm missing on these "older" models (not that iPod Classic 2009 or iPod Nano 7g 2012 are young) is the earphone remote control (e.g. of the cable EarPods).

Apple did a really great job on remote controlling the devices with "tap"-Codes (tap, double tap, triple tap). The iPod Classic 2009 for example does not support the codes for fast forward / rewind (tap+tap_hold=ff, tap,tap,tap_hold=r). That's something I regularly use for audiobooks, so I'm tied to the iPod Nano 7g (the 6g would also work, but I prefer the larger display for navigating chapters).

There are android devices supporting these tap codes partially, but not as good / reliable as the iPod Nano 7g. Android also is using OMTP while Apple is using CTIA, so Apple headphones won't work on android and vice versa. CTIA=>OMTP Adapters (from amazon) just switch the pinout, which does not work, because Apple uses different Resistance on the Pinout.

I also "modded" one of my iPod Nano 7g by partially milling out the aluminium backplate and soldering in an iPod Mini battery (600mah), so that I got nearly 3 times the battery life of a factory iPod Nano as well as an easy to replace battery without opening the device (which is way to hard). The bigger iPod Mini battery does not fit without a silicone bumper, but since I already used one, it was perfectly fine. Changing the battery still requires soldering, but at least not fiddling with the very fragile display removal procedure.

However, currently I did not find a better device for my use case than the iPod Nano 7g. And everything is better with bluetooth... although I don't use it :-)