If you want a longhair friendly company to work for try working for a guitar company... they dont seem to mind. This is a picture of USACG shop, count how many longhair is there!
USACG shop picture...Yes there are a few in the picture.
I work in IT myself and it's generally a longhair tollerant industry and never had an dress code issues, even if I got a few grey hairs!!!
John.B
In some circles of the IT industry the length of one's ponytail is actually considered a status symbol indicative how long one has been in the field. Generally, any field that demands "substance over style" will be longhair-friendly; it's where "suits" call the shots that a longhair is likely to run into grief.
That's pretty cool.
Pretty much anything, I would imagine, having to do with rock music will be tolerant to longhairs.