Require Assistance with obtaining documents for a visa

A client of mine is applying for a residency permit on the basis of Živnostenský list in the Czech Republic. He is Microsoft certified in configuring, managing and troubleshooting Microsoft systems, Networking and Security. He is a Turkish citizen. Due to the process being far more difficult for third country nationals who are not from Canada, the USA, Australia etc our agent advised us that getting a letter of intent to cooperate with some companies in the Czech republic would be ideal. He already has long standing clients in Turkey so getting clients in the Czech republic is not an immediate concern as he will continue to cooperate with his existing clients, but we are interested in any Czech companies (preferably in the IT or related sector) that could issue a simple letter stating intent to cooperate with him and use his freelance services. We do not require a contract or anything legally binding just something to add onto the application with no commitment to strengthen our visa application.
Any serious parties feel free to reply for more details.