There must be a way for you to solve this. For example, could you convert your desk to a standing desk by putting a sturdy box on top of it? I did this for a while using a wine box that happened to add just the right amount of height.
I was only using my ThinkPad at the time, no external monitors, so I didn't need to raise the whole desk. You could even accommodate a desktop keyboard and mouse using a bigger box.
If this works, your team will be impressed by your scrappy inventiveness! :-)
I've suggested getting a treaddesk (treadmill desk) at work more than once, with co-workers, direct managers and company execs, but presumably as no one else has tried one, everyone looks at me funny when I ask. So I tend to split my work programming time between workplace and home as a compromise...
Then there's the Vivo Barefoot shoes I've been recently trying for increased awareness when walking, and better walking ergonomics... at this point it seems like a safe assumption that most things humans habitually do aren't ergonomically optimal. ;-)
Desk and chair heights seem to be pretty standardized so even if there is a hodge-podge of chairs around they're all the same height. I'm definitely taller than average, but a quick search says only by about one standard deviation, so I can't be that unusual.
In general, it does seem like there's a stigma against office comfort, at least in small to medium startups that I've worked at. Usually everyone is using the same shitty, half-broken desks and chairs that came free with the office lease, and the already independently wealthy founders will brag about how scrappy the company is and how proud they are of not wasting any effort or money on something as banal as office comfort. In that environment if you ask for special equipment you're really made to feel like you're being difficult.