It might be field dependent, but I have only seen technical reports published by companies (if similar to technical notes) and professional organizations (like TAPPI).
But nevertheless, peer-review aims at improving your work, giving it more credibility, as it has been reviewed by your peers and they concluded it is (in their opinion) valid, or rejecting it if it is performed poorly (not exclusive list).
So publishing in any place other than a regular journal might affect your work's visibility (I'm not sure the power of Google can bypass this issue) and your work's credibility (as I'm not sure I would consciously cite a work that is available only as a pre-print and not peer-reviewed).
As for the problems you present:
- Money. I'm currently not affiliated to any academic institution which would reimburse my conference fees and publication costs. I
would also like to provide open access, so other non-affiliated
researchers can actually read my paper. This can be very costly.
I understand the issue here, but when I was in institutions that had no money to cover the open-access publication, the non-open access option was the only alternative. Unfortunately, you probably can't have the pie and eat it too...
I can't comment on conference fees, as in my field, conferences don't count as publications.
A middle solution could be to choose the non-open access option of the journal you select and publish a pre-version or even the accepted version of your manuscript as a pre-print with a link to the official (but not open access) pdf (you could ask the journal policies on this matter). In this way, you provide all the information through the repositories you choose, the manuscript is peer-reviewed, and the article is indexed and available for those paying the paywall.
- The topic. It's an interdisciplinary thing I write about, which doesn't really fall into the field of interest of the usual journals and their
peer reviewers. It's a bit of an in-between-the-chairs thing.
Most works in my field are interdisciplinary. You can usually identify the main field of the article and find a respective journal. In most cases, you can propose reviewers, so you can select ones from the different disciplines your manuscript covers. Each then can concentrate on the part they are more confortable to review, covering eventually all aspects of your work.
Finally, if you insist for a technical report, you might be able to contact a relative association or company directly and discuss if they are interested in your work and a publication under their technical reports (but I admit that I have no experience on this and I might be completely out of subject).