I know some people who have trekked from Shimshal to the Braldu Glacier without any permits, although technically it's in a restricted zone as it's very close to the Chinese border. If you ask around in Shimshal you should be able to find some people who have been this way that you can hire as porters. You'll be at their mercy regards how many stages they ask for the trek. I've thought about trekking this route myself.
Regarding guides, many of the good Shimshali guides are often not in Shimshal during summer as they are often hired for high peaks. You're therefore best trying to arrange something in advance. You could try contacting this shimshali although he's currently part of a winter Broad Peak attempt:
Some British went this way many years ago. They included Steve Razetti who has some good photos on his website:
They climbed Bradu Brakk if I remember, which is the peak by the Braldu Pass.
Just in case you're considering it, I wouldn't do the trek in the opposite direction. The Hispar porters are often a bit of a nightmare just trying to get up the Hispar Glacier without problems and strikes.