Ask HN: searching for mobile wireless POS printer

Dear HN-crowd, I am in need for 'mobile wireless printing devices' that can be programmed to be integrated into our wireless hotspot network. Please let me explain, how I would like to use it. Then I will explain some technical needs. Goal: Salesmen, using the mobile device to sell access credentials. Those salesmen have to be accountable. The ideal solution would have only 3 buttons. '+' and '-' to select an service id from a list of predefined services. 'Enter' to confirm a service and print out a receipt including access credentials for our hotspot system. On a more technical level, I would like to store some key-value pairs on the device to identify the salesman and available services. When the 'Enter' button gets pushed, I would like the device to send out a (ssl encrypted) web request to our billing system. Depending on the answer (error+message/success+password), the device should print the receipt. I hope my explanation makes sense and is somehow understandable. I would be very happy if you could direct me to a vendor that could help me on this issue. In case it helps: we are in need of several hundred devices. Thank you for your time. (you will find my email address in my profile) btw: IPhone + printer + duct tape is not really an option. But I am open for other creative approaches. :)