Dear …
RE: Proposal Requested for __(Project Type)__
__(Company name)__ has recently __(expanded its operations/accepted a project name)__ and we invite you to bid on __(project name)__. This project is quite complex in nature. Therefore, the hand-selected companies that have been chosen to bid on this project have come equally referenced and recommended. __(The presentation you made on the __(type project)__ back on __(date)__ made such an impression on us that we wanted to invite you bid again on this project)__.
__(Enclosed/Attached)__ please find our specification sheet outlining all the requirements and details for this project. We ask that you submit your proposal no later than __(date)__ so that a fair and professional decision may be reached as soon as possible. All proposals will be reviewed very carefully.
Please don’t hesitate to contact me directly at __(phone #)__ if I can shed some further light on this project for you.
Sincerely,