You can use handbrake with an output size of <4096mb, however you will notice a drop in quality, re-encoding x264 video is a fundamentally flawed process which you should avoid at all costs. Just know that if your video has DTS audio, handbrake will only allow you to re-encode to 2.0 AAC, it will passthrough AC3, however.
Something to bear in mind, most 720p x264 rips available contain DTS audio @ 1.5mb/s, any DVD5 (4.37GB) size releases you have can be shrunk to <4GB by re-encoding the DTS to AC3 at 640kb/s. However, that's a bit more of an advanced process, go ahead if you're familiar with demuxing, muxing etc. Wont work for 1.5xDVD5 (6.6GB) or DVD9 (8GB) though.