As of this writing, and in alphabetic order, these companies offer 3D printing/additive systems that use stereolithography, or a version of stereolithography, to build parts layer by layer. You may find a number of companies making stereolithography systems for less than $1000.00, but these systems tend to fit the needs of non-engineering professionals.

3D Systems: these include the ProJet 6000 HD, ProJet 7000 HD, ProX 800, and ProX 950

B9 Creations: Core 530

Carbon: a version of stereolithography they call Digital Light Synthesis enabled by the CLIP process

EnvisionTEC: Vida 3D printer is one, but the company makes a number of DLP systems.

Formlabs: Form 3, Form 3L,

Stratasys: V650 Flex 3D Stereolithography printer