The 70d won't pack twice as large. A good bet (with a bit of fudge factor built in) is about 1.5x the size. Which is still not huge when bundled with an hammock compared to a full-sized 1-man tent with a PVA footprint.
However, it won't last quite as long (as MAD777 notes) due to delamination of the coating. Now, that won't likely happen for years, so feel free to use one if you choose.
Another thing to consider is the sunk cost of gear upgrading when you do finally get more cash. Is it worth buying cheaper gear now and then not being able to sell it down the road, thus losing some of its value, when you decide to upgrade to lighter, more expensive gear?
For me, it was worth that; it got me out there and made it possible for me to learn the basics of backpacking. For you? I dunno; only you can answer that.