Lance,
I will have a go at answering your questions. Others may feel differently as opinions differ.
If you are dissappointed by the performance of an ELB this could be for a number of reasons. They could have been poor bows. As well made english style longbow should shoot well and with minimal or no handhsock. It will however not shoot as snappily for the draw weight as a modern recurve or as smoothly. When compaired to a modern bow an ELB could thus be dissappointing, but it can only be what it is, a traditional simple wooden bow.
There is a huge range of Longbows in use here in the UK. Some made for the re-enactment market here are terrible. May eb the same whereever you are. Reenactors want something that looks the part, but often want low performance in order to be allowed to use them. A reenactment longbow almost certainly is not a proper longbow by anyones definiton. If these are what you have tried I am not suprised that you are dissappointed.
A well made longbow, even at a draw weight of 45lbs or so can send a target type arrow well over 200 yards. There are many good bowyers, but there are also many bad ones. If you see a bow you like and the archer using it also likes it then that may be a good reference.
120lb bow! if you do get one or make one make it very long. This may make it perform less well, but it will be a lot easier to draw the weight and will be more durable.
I cannot really answer your speed question. I have never measured arrow speed. All I can say is that the bows I have made have been fast enough. I have seen some very poor bows with huge amounts of set and very poor cast. This is why it is a good idea to follow a good pattern when you make your own, or to buy from a bowyer whose work you have seen.
An ELB with some reflex may perform better, but may be less accurate. The arrow may be faster but not go to the right place. My personal preference would be a longbow that had a little set once shot in, maybe an inch or so, spread evenly along the working limb. This would indicate that the bow is evenly stressed and is using as little wood and mass as possible to do the job. It will aslo be pleasant to shoot and stabel, forgiving and accurate.
I think that Pip Bickerstaffe's book Heritage of the Longbow is probably the most helpful in terms of information for making an ELB.
Some ready made "ELB" balnks sold in the US are not really ELB pattern. Some are basically american longbow style. Make sure you would be getting what you want. It really isn't too hard to get some Ipe, get a hickory or bamboo backing and make your own bow from start to finish. I do not know of people making yew bow blanks.
I would advise that you get at least three of four laminated bow under your belt before attempting a self bow. Make a few self bows in hickory and ash before ruining your first yew stave! Almost everyone has done this! It really does make sense to practice and improve your skills on cheaper woods before trying the most difficult bow in yew.
I would not advise sanding down the nodes on bamboo. bamboo is there to be the backing and gives power. Sanding down the nodes gives areas of power and weak areas. i doubt that a rawhide backing would prevent the bow breaking where the bamboo fibres were cut through. If you want a traditional look use hickory as a backing material. This can look very like yew sapwood. A hickory backed Ipe bow, or hickory backed Osage looks very nice.
A good bit of yew with intact sapwood needs nothing else. they are the perfect natural compression/tension companions. Adding bamboo would eman that you need to violate the growth rings and add weight (bamboo is heavier than yew) for no real gain and the bamboo may well crush the yew belly and cause chrysals.
If your heart is truly set on a bow with a flat trajectory they perhaps you should look for another style of traditional natural material bow that would give you this. A longbow can shoot flat, but perhaps not as flat as you are used to. After a while of shooting longbow you do adjust to the somewhat different trajectory. Though more challenging to shoot well, longbow can be great fun.
Mark in England