The jets I have flown have had pretty pokey little cockpits (although not as bad as the Mig 21 I once sat in)
I'm 1.72 m and 62 kg, and I fit in the '21 very nicely. You must be obese. Obese people should not be in the military. Ever.
Besides, a military jet is a military jet, not your bedroom. I've ridden in a number of recent American products and have felt horribly exposed. Semi-reclined seating? How can you fly and fight when your genitalia are almost obscuring the HUD?
Flying balls-first into the wild blue yonder is not my idea of fun...