Be careful with your terminologies here. Use of the term "GFCI" is narrowly defined as being a "Class A" ground fault protection device, which is intended for PERSONNEL protection and trips at a MAXIMUM of 6mA of ground current. The IEC style "ground fault breakers" described in the pervious posts are not UL listed as Class A, so they cannot be use for the same purpose.
So start with why (or if) you really NEED a Class A (GFCI) device. Many people tend to over interpret this requirement. If you read the NEC, the only times that you need a GFCI is when you have PLUG-IN equipment that is or could be in a wet invironment, i.e. bathroom, kitchen, outdoors, or if it is a swimming pool or spa, or if it is a carnival or circus. If it is one of these cases, for example a 240V portable pump that is going to be plugged into an outlet, then you will be forced to buy a small CB load center to plug the breaker into, because Class A GFCI breakers must connect to a Neutral bus, not just a ground bar. You can however get very small load centers that only hold one 2 pole breaker, often referred to as "spa panels" because that is a big market for them.
If you have a simpler requirement for "Ground Fault" protection on equipment, but is not related to personnel protection, that does NOT necessarily need to be a GFCI (Class A) device, in which case the IEC versions (if UL listed as a circuit breaker) may suffice.