I have pondered flipping the fans over, to blow out the top, however in my set up (the shop electrical room) the max temp ever in that area is only 24-degrees C (75F) so I didn't bother to change them. One day if the fans wear out maybe.
Putting them in a rack may work for you, especially if you have a separate monitoring system connected, like Solar Assistant. (I do, and love it) so you will not need to access the equipment itself very often to adjust settings, once it is set and running. My own three inverters are set up with only the 'master' easily accessed, since the other two just follow orders from that one. Most of the time I make changes from solar assistant from my phone or laptop without even going to the electrical room physically.
I wouldn't want to be kneeling on the floor to connect the inverters or anytime something needs attention, maybe this will be infrequent once you have it running.
To hold the wider inverters you need a wider cabinet, I wonder if you can add full extension drawer glides to a file cabinet or a large steel tool box. The trick will be finding one the right dimensions - or build one as 12Voltinstalls pointed out. I have built my own racks for my DIY battery packs, and these use small steel angle and some light welding, & spray paint. Some of the members on the forum say used server racking is tossed out 'all the time' as they do upgrades in IT work. There are wider racks available - maybe you can source one, or modify a rack to hold the wider inverters.
I have to agree the form factor of putting batteries in a rack but the inverters and most of the other equipment on a wall, has always seemed awkward at best. My DIY racks are 30" deep but the inverters are only 6", putting a stack of batteries between two or three inverters doesn't work very well. We want the batteries close to the inverters to keep the large wires short as possible, but then we need to put the rack to one side, often in a corner, to deal with the dimensions of the rack. Then to connect it together we end up running electrical trough between them to contain the wires. I have been planning an upgrade to the solar that will change from three 6kW inverters to two 12kW, taking less wall space. The battery server rack will fit into a purpose built jog in the adjacent wall, 24" x 32" just to suit it's dimensions and maintain access to the front for battery removal/insertion/maintenance.
I have wondered about designing a partition wall set-up, with stacks of server racks on one side backing onto a partition to support the Inverters, heavy cables run straight through the partition from the rack batteries to the inverters - no trough. Wouldn't fit in my current space, but interesting to think about alternative layouts from what we always see posted. Good luck with your project, it would be interesting to see what you end up with.