Renatar: I have done that. I have checked the priest in Hillbrandt every single time I was in town and have never seen the spell, the same in Glatzburg....
Actually, it will eventually appear if you keep trying to reset their inventory. I have tried that and it appeared after a number of tries. If the priest doesn't sell it, try checking with the innkeepers. The spell scroll costs nearly four times the price of other spell scrolls of that level so it doesn't appear in merchant inventory often.
There is a console command to add a spell scroll to your inventory but it is really time-consuming as the console command only adds a random spell scroll and not any specific spell scroll. I have tried generating more than 200 spell scrolls with this method and the Raise Dead spell scroll did not appear even once using this method.