How is the DT-235, M30 and SRH-240 not considered portable and full size? They're very small, especially the DT-235.
I also don't think you can find the MDR-V6 for $50 unless you get a used pair or get lucky. They retail for $100 usually.
Since the Koss UR-55 is about the same size as the SRH-240 I'd suggest that. It's especially good for rock music like Pearl Jam. The comfort is good on them as long as you don't have a huge head. I find they sound far better then my Porta Pro and are more comfortable and a lot larger.
I also do like my DT-235. They sound really good for the price of under $50. They're not the most accurate headphones ever, but I don't really have any complaints about them. I'm glad I bought them. Strangely, I like the vocal quality on them more then the DT-770 and 880 I've tried! Not sure why that is.
M30 is very, very boring, but I like them at times and will keep them. It seems completely neutral and it's hard for me to suggest them. For people that say the SRH-840 and k701 is boring, wait until you try this! I prefer them to my old MDR-V6.
I'd take M30 off the list because it's not all that easy to drive. Really needs an amp.
EDIT: DT-235 has no head clamp for me at all. It's very loose, but comfortable. Feels secure though.