TiLDA Mkπ badge they had a pile of TiLDA MKe badges from the 2014 event on sale.
These are not as nice as the 2016 badge, but given the knock down price a really good platform to mess around with.
It's an Arduino Due, Ciseco SRF data radio, black & white LCD display, LiPo charging circuit, 3.3v LDO regulator, accelerometer and assorted buttons/lights on a single board plus a battery to power it.
Given I already had on my radar that I wanted to build something that was a 'handheld unit with display and some kind of wireless comms' to use as in-game props I snapped some up. I have been using SRF radios extensively already, going so far as to write my own networking protocol for them, so it's almost like these badges were tailor made for me.
Having been professionally designed and made this is far better than anything I could hand solder in my cellar and will save me an absolute ton of time. They do lack WiFi but I have a load of ESP-01 ESP8266 WiFi modules which should be fairly easy to piggyback on and squeeze into the case if I need this.
Somebody has also come up with a 3D printable case for them so I've quickly printed one out. It's not a perfect fit, being slightly too shallow to close with the battery inside, but the source files are online so this has got me even closer to a finished device.
Now it comes down to writing the software and I'm experiencing version/dependency hell in the Arduino IDE so can't even upload 'blink' yet. The library files on the badge Wiki are made for an old version of the IDE so I suspect downgrading to the version they mention may well fix this. Once it works at all I'll try to rework things into a format/version modern versions of the IDE will deal with.