I don't like the idea of buying drip irrigation and tossing it away 5 years later, so I was wondering if using furrow irrigation on 30" beds for quick growing crops would be possible. Would I have to water freshly sown beds with cans until veggies are established?
My first instinct is to say in most circumstances it can be very effective. I think this is one of those areas where it depends on your circumstances. The rule of thumb we used in our garden, when we put a wicking path in, is that capillary action can carry water up 12 inches; but that number probably varies depending on the soil conditions.
The closest we've come to furrow irrigation in my garden is the wicking path. We filled a trench with organic matter between two raised beds and have emptied a 500 gallon cistern into it at one point without having overflow out the other side. The water slowly releases from that central trench and we have tomatoes, peppers, and sweet potatoes that were never watered this year. They survived solely off the water wicking out of the trench. To be fair, the pepper plant didn't do so well. The tomatoes are covered in fruit right now and we've got what looks to be a great sweet potato crop. I don't know it this could be relevant to your situation.