Can anyone suggest a flowering vine that can reach the top of a two story house?

I live in Central Texas (zone 8b). The longer it blooms the better.

Rambler roses a perfect fit if you can provide them with minimal care (watering regularly during droughts, fertilization and a little training pruning and tying). Check Super Dorothy as an example of modern ramblers.
Large climbers like Altissimo are almost as good, but require more care with pruning and training.
Check blooming duration: both rose types can be once blooming, continual or repeat blooming. With continual blooming you can enjoy months of blooming during the Summer, but remember to provide extra nutrition (especially phosphorous and potassium) to have larger and more colorful blooms.

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I ditto the ramblers-
if you want something faster, Im a huge fan of trumpet vines- because the hummingbirds LOVE them and they grow like nuts- but you'll have to weed=n=fed the lawn n front evry year to keep sedlings down.
But no matter what you do- build a terrace thats at last 12" from your siding unless you want them growing under your siding and ripping it off your house-

A beautiful climbing vine is a wonderful addition- but please don't let it climb ON the house becasue it can pull it apart i ways youve never imagined. Give it a trelise so it clings to something other than your structure!

Climbing hydrangeas are also quite spectacular, bloom long and smell fabulous - but again- give them a trlise and keep them off the house

climbing roses are the least invasive when coming up a wall that high