This is an announcement for the paper "Spaceability in Banach and quasi-Banach sequence spaces" by G. Botelho, D. Diniz, V.V. Favaro and D. Pellegrino. Abstract: Let $X$ be a Banach space. We prove that, for a large class of Banach or quasi-Banach spaces $E$ of $X$-valued sequences, the sets $E-\bigcup _{q\in\Gamma}\ell_{q}(X)$, where $\Gamma$ is any subset of $(0,\infty]$, and $E-c_{0}(X)$ contain closed infinite-dimensional subspaces of $E$ (if non-empty, of course). This result is applied in several particular cases and it is also shown that the same technique can be used to improve a result on the existence of spaces formed by norm-attaining linear operators. Archive classification: math.FA Mathematics Subject Classification: 46A45, 46A16, 46B45 Remarks: 9 pages Submitted from: dmpellegrino@gmail.com The paper may be downloaded from the archive by web browser from URL http://front.math.ucdavis.edu/1005.0596 or http://arXiv.org/abs/1005.0596