At 26 GHz, you're not going to find a lot of inexpensive options nor a lot of companies with the capability to even make them. The big players are Keysight, Rode & Schwarz, and Anritsu, and any of them likely could deliver something that did what you want - but what do you want? How many ports? Do you need multiple sources? And maybe most importantly: do you have personnel trained to use them? If you're looking at 40GHz, even individual calibration standards and cables will be north of $1k USD, so you really need someone leading the lab that both knows how to handle the equipment properly and knows how to train people to do it. If you've got that person or people, while no offense to you, it's probably a decision they should be making.
That said, they know you're an intern, maybe they're looking for you to scout around for potential options, possibly finding options they haven't already considered. In that case, maybe taking a look at some RF trade shows or information from them could help you find potential alternative vendors (though if you're getting a VNA for a lab and you don't already have one, I don't know if I would go with an upstart, honestly.)