Sure! You can get the screens on eBay and the usual places. Check out
this one, for example. Looks like about £50 shipped to the UK. That's the 9.7" full iPad version, though, so it may be slightly big for the SE. The 7.9" Mini version might work better, if it's supported!
There's an article about the converter on
hackaday, and you can buy a complete set of assembled converter + display from the creator in Southampton for £110
here. It's supposed to be open source, but it doesn't look like the creator has released it yet because the schematics are still a gift on Kickstarter.
It uses the all-too-familiar ATmega 32u4, so you could probably save most of the money by just using a Pro Micro and doing it all yourself.
On the Kickstarter page, it does say the following:
kickstarter wrote:
"PLEASE NOTE: OSCAR is ONLY compatible with DisplayPort / mini DisplayPort and Thunderbolt"
Which might be an issue for a C2D-era Mac Mini.