One solution is to get a Sinar f or p with a bag bellows ,you can use a roll film back with ease and for digital there is the option of a sliding back or less ideal, an adaptor back which allows you to put a P45 on to a hasselblad film back fitting. I Have used the sliding back years and it works well . This option also allows you to expand your kit with endless amounts of Sinar equipment which can be had at a very good price indeed .