Yes, you can repaint muslin backdrops.  Our local community theatre has some 20 year old drops that have been repainted 3 or 4 times!  However, a new drop painted just once weighs about 40 pounds, while some of their old drops now weigh 100 to 150 pounds!!!

 

 

One of the beauties of this paint was that you could easily make any color you wanted in any amount rather than having to go back to home depot to buy another can. I tried to get our group interested in Rosco supersaturated paint because it forces you to make up your own colors that can be much better suited to theater. I think they felt that it was too expensive. I felt that it was actually cheaper in the long run. Even though a gallon of supersat cost much more than home depot paint, it goes a lot farther, and you only mix up what you need, making it somewhat cheaper. I couldn't sell it here.

 

As to the "animal glue" I assume that this is what you get after sending the old gray mare to the glue factory. It came as crystals that you cooked in a double boiler. It smelled really bad especially if you let all of the water boil away.

 

Printing on Chameleon Scrim is cheaper than people think.  It costs $50 plus $1.5/sq ft plus the price of the scrim. 

 

But if that is beyond a budget, consider painting Chameleon Scrim yourself.  Its fairly easy to paint and instructions are on the company website.  http://studio-productions-inc.com/white_papers/wp_painting_scrim.html  a 15' x 30' costs $ 450  (Remember to treat with a flame retardant after the painting).

 

Finally if painted scrim is beyond your budget, consider renting a scrim ($195 two week rental of a 15' x 30' scrim) and projecting the set with a projector or shadow projections.  Its easy to do shadow projections for Seussical.  I'd recommend the lavendar 15' x 30' scrim to get the odd skies.