Rat Bikes! Pub Bikes Beaters! Frankenbikes!

Anyone want to suggest some frame mods for this? Literally anything considered as long as it's cheap and doable by a complete novice (no replacing headtube etc. for now)

(Ignore my awful cabling, I'm just making do until I weld these bits on)

At the moment I am thinking:

1. ditching the band-on shifter boss and welding a downtube boss on to the top tube
   
2. disc brake tabs (plus a strut for reinforcement) on the rear
   
3. cable tie guides down both seat stays for full length outers.
   
   

Just want to learn a bit of welding and this frame is my test bed. Any other suggestions? Some parts for a dynamo might be fun but not sure what's needed for that?