Never seen anyone Taxi out with one at my company (737NG), we are also a procedure crazy company and there is no documented procedure for taxi out on one so I would be very hesitant to try, because for sure if you made an error and took off with the Packs or bleeds misconfigured you would be shot! More then all this however is that we mainly operate to secondary airports, where taxi times in and out are very rarely more then 5 mins, in which case you need to allow time for warm up and cool down anyway.