DIY Laser projector guide?

[Pyper]

Can anyone point me to a make-your-own-laser-projector guide?
I have a couple of the cheapie SD-RGB500s and they are fun!
I want to build my own to display ILDA animations on the side of my work building (white, 160 feet wide).
We experimented with R, G, and B laser pointers and they looked great!
I'm not sure where to start. Lasers? Galvos? Lenses? help!
I see the 'fat' lasers on ebay, those may be fun!

 

[Mattronium]

What is your goal?
Buying one is usually cheaper than making one. The main reason to make one is to customize it or as a learning experience.
I made a simple projector nearly from scratch for a project, so I can answer some questions on aspects of what I did.

 

[Pyper]

Well, I was going to buy a lasercube but to be honest I am worried about putting it in a location I can't constantly monitor.
I'd rather build something similar and just put the fewest electronics necessary outside to project the ILDAs and have everything else inside.

 

[Pyper]

Is this a good unit to start with? It says "Analogue RGB 3000mW White Laser Module/Combined by 520nm+638nm+450nm Laser"
Check ebay item 141871909008
What else would I need?