Good question...I'm not sure that any panels are OK to be mounted vertically. Most of what we see around here are the lack plastic mat panels, and I don't think the manufacturers of those products would recommend a vertical installation. That being said, a vertical installation will not be very efficient; think of the sunlight as a "glancing blow" on the panels since the sunlight is coming from above. If you want to get the best performance out of any panel, it needs to be mounted perpendicular to the sunlight.
Another thing to consider: while many HOAs may not like something like solar panels, in many areas (mine, for example) they are not legally permitted to interfere with the construction of any "alternative energy" system that someone wants to use. So, while they may not like it, they may not be able to do anything about it. But, why not just ask them? HOAs get a very bad reputation but there are many that are reasonable.