I have an Eheim classic 2215 and I would say that 29 gallons is about the limit of that filter. I wouldn't use it on a tank 36'' or longer in length (i tried in on my 50 gallon tank and it wasn't adequate... i have it on my 30 gallon cube now and it's fine).
As for the lily pipes, i have to disagree with everyone that suggests ebay and instead consider (1) the amount of money you want to spend and (2) the quality of the lily pipes you want. Yes, ebay has lily pipes, but not all lily pipes are the same and rarely do people mention that. Here are my considerations for lily pipes by brand (and only some can be found on ebay) ...
Power Man - CRAP!! DO NOT USE!! These lily pipes are the cheapest to purchase, but are of awful quality - The glass is way too thin and easily broken and the slits on the intake pipe are poorly cut at best, not even cut at worst. I would totally avoid this brand.
ANS / Aquatic Magic - I've used the ANS brand and they look very similar to the Aquatic magic brand (which i haven't used). The glass is a decent thickness and the slits on the intake pipe are good, but the quality of the work is ... lacking compared to the ADA brand. I'm not a big fan of the intake pipes simply because there are so few slits on them. (This probably more important on higher capacity pumps, however)
CAL Aqua Labs - I've never used them, but they get good reviews on quality. I don't like the lily pipe, however, because it directs the flow down, not across. Plus the 17mm intake pipe is almost never in stock @ GLA...
ADA - The quality of the glassware is amazing. It's very strong and very clear. Plus, there are a lot more slits on the intake. Definitely worth the money, if you can afford them.
Do! Aqua - The consumer line of ADA, i haven't used them. That said, the lily pipes are designed differently than the ADA ones, so they aren't really a direct replacement for them... The intake pipes are a direct replacement, however, and many people say they are a good compromise on quality and price.
Borneo Wild - Another premium line of glassware, these look comparable to ADA in quality and price. I have not used them yet, but I really want to (when i get more money, of course).
Gush! - The consumer line of Borneo Wild, these look like decent quality glassware, but i have not used them. They seem to have knockoffs of the ADA lily pipes (and intake pipes) and the Do! Aqua poppy shaped lily pipes (and intake pipes).
Just some things to consider...