Where do you go for supplies? For starters check out these aftermarket companies for alternative sources of automotive lacquer:
MCW Automotive Finishes
Rainbow Paint Products
Black Gold - House of Kolor
Or, better yet, see if there's an automotive paint supply store near you that deals in PPG or DuPont products. Buying bulk items like thinner, primer and clearcoat will save you a lot of money at these stores and will last a long time. These stores can also formulate virtually any color you might be looking for although in most cases the smallest quantity they'll mix is a pint. Sometimes you can talk them into mixing a half pint but not often. It doesn't hurt to ask. You might find it more cost effective to buy bulk items at these types of stores and order your paints from the aftermarket. This is a combination I always encouraged, especially with thinner.
If you can find these bulk items locally I highly recommend buying them:
DuPont 615S VariPrime                                      (1 quart - $39)
DuPont VariPrime 616S Converter                     (1 quart - $16 or 1 gallon - $49)
PPG Duracryl DCA-468 Hi-Performance Clear    (1 quart - $25)
PPG Duracryl DTL-105 Lacquer Thinner             (1 gallon - $22)
That's it. Other than these items all you'll need are the actual paint colors. The costs may seem high to buy these items all at once but ounce for ounce you'll be saving a lot of money, the shelf life of the items will last for years, and they're all among the highest quality products available. If you're planning on sticking with lacquer for your model finishes it would be a wise decision to purchase these items.
I hope these suggestions prove helpful!